INTRODUCTION: Lithium is a metal used as a salt for the treatment of acute maniac episodes and for afetive bipolar disorders profilaxis. Patients with acute kidney failure (AKF) can become intoxicated fastly when taking this drug. Our purpose was verifying lithium influence in rat locomotion of na AKF surgical animal model. METHODS: It was used 61 wistar rats with one week lithium treatment previously to unilateral nefrectomy. Thirteen rats induced to AKF. It was administred lithium or fisiologic solution and after that we checked their locomotion and serium creatinine. We had done statistic analisys. RESULTS: Creatinine was increased in AKF rats. Lithium treated AKF rats showed less locomotion, demonstrating na inverse relation between lithium blood and locomotion. CONCLUSION: AKF animal model was effective. AKF rats treated with lithium showed locomotion alteration compared with the others. Lithium blood increase leads to proporcional decrease of rat's locomotion.